1. Field of the Invention
The present invention relates generally to an electronic document management method and program in which an electronic document file kept by a host server is copied onto a plurality of subordinate servers such that clients can utilize the electronic document file, and more particularly to an electronic document management method and program ensuring an effective transfer of the electronic document file from the host server to the subordinate server depending on the status of utilization of the clients.
2. Description of the Related Arts
Recently, electronic document management systems for computerizing and handling documents essential for corporate activities are being put into practical use, and their consequential paper-less operation can reduce costs required for printing, sorting, delivery, storage, operation, etc. of documents, and improve efficiency of work and quality of work. In such electronic document management systems, electronic documents created by a mainframe, office computer held by a corporation, or general applications including Windows (R), and further by a variety types of accounting packages are stored in a server that runs in a Web-based environment, such that the electronic documents can be used from a head office, department, business office, branch office, or further from a client at business partner. In order to practically share the load of a network and server, a decentralized electronic document system is proposed, in which an electronic document is shared by a plurality of servers. Many of such decentralized electronic document systems employ a hierarchical structure reflecting the organization of a company, such as a host server representing a head office of a company, and a subordinate server representing a branch office of a company. In the decentralized electronic document system, an electronic document file kept by a host server is copied onto a subordinate server, such that a user looks up the electronic document file using a client computer connected to the subordinate server. Also, in the system, an electronic tag can be added when a user looks up the electronic document file of the subordinate server. In the following description, the addition of the electronic tag to the electronic document file is defined as the change of the electronic document file. In the decentralized electronic document systems, when the electronic document file that is changed by the addition of the electronic tag in the subordinate server is copied onto the host server, in order to reflect the change into all subordinate servers, the changed electronic document file is copied onto all subordinate servers across the board. Also, a competition takes place when a change is made by the addition of the electronic tag to the same electronic document files in a plurality of subordinate servers, and the changed electronic document files are copied onto the host server at the same time. In the conventional systems, when a competition of changing the electronic document file takes place in the host server, as described above, only any one of the changes made in the plurality of subordinate servers is reflected into the electronic document file of the host server.
However, in the conventional decentralized electronic document systems, when the electronic document file is changed in the subordinate server, the changed electronic document file is copied onto all the other subordinate servers, after being copied onto the host server. This increases the data transfer amount on the network and the number of transfers, and also increases the load applied to the network. Especially, even if the changed electronic document file is copied onto all of the subordinate servers, there is a high possibility of copying the electronic document file with few possibility of being looked up or changed, depending on the subordinate servers. Because of copying the electric document file, that is not required to be copied, onto the subordinate server, the data transfer amount on the network and the number of communications are increased, and thus the load of the network is increased. Furthermore, as the subordinate server has to keep the electronic document file having no possibility of being looked up or changed in the subordinate server, there is the problem of higher facility cost, to meet the requirement of larger storage capacity, and beforehand arrangements for providing excessive storage area for storing the electronic document file which would be rarely used. In addition, when a competition takes place because the electronic tag is added to the same electronic document files at the same time in the plurality of subordinate servers, there is the problem that only a specific electronic tag is reflected into the host server, and the rest of the electronic tags would not be used.